In loudspeaker devices an acoustically active material may be placed in a back volume of the loudspeaker device so as to virtually enlarge the back volume. Such an acoustically active material may be an acoustic volume increasing material which virtually enlarges the back volume. Hence, by use of an acoustically active material the resonance frequency of the loudspeaker device is lowered to a value that can be achieved without acoustically active material only with an essentially larger back volume.
EP 2 003 924 A1 discloses a molded gas adsorber obtained by adding a binder to a porous material including a plurality of grains, thereby forming widened spaces among the grains of the porous material as compared to a conventional gas adsorber including no binder. The binder is provided in the form of a powdery resin material or a fibrous resin material.
Forming a molded gas adsorber that provides good adsorption/desorption characteristics from grains of porous material and powdery resin material or fibrous resin material may be difficult and expensive.
In view of the above described situation, there exists a need for an improved technique that enables to provide an acoustic element while substantially avoiding or at least reducing one or more of the above-identified problems.